How would I get an array out of a table?

For example, if you've ever used Kohl's Admin Infinite and tried to make a custom command there's the argument type 'player'. Specifically it says this:

'player' -- returns an array of Players

And when you're indexing the argument of players you say args[1] which is the array of players. Explain to me (please) how the array works and how I would continue my command (it's basically a TP command).